In general, a mobile Internet protocol (IP) is a protocol developed to support frequent movement of mobile nodes. It has been suggested and standardized in request for comments (RFC) 2002 by an Internet engineering task force (IETF) mobile IP working group. In the above mobile IP environment, when a mobile terminal registers an address obtained in a current network to a home agent (HA) when accessing a remote network from outside, the HA transmits data to the remote network. Such a mobile IP standard includes mobile IP agents and mobile nodes, and the mobile IP agents perform a virtual routing service for routing packets to a registered mobile terminal.
The mobile terminal is required to be informed of an IP address of a service providing system. However, IP addresses are usually given in digits, and therefore it is difficult for users to memorize the numbers. Accordingly, domain names formed by characters which are easily memorized by the users are provided.
A domain name server (DNS) includes information on the IP address of the service providing system and a corresponding domain address, and provides an environment for converting a service requested by a user IP system as a domain name into an IP address. Accordingly, a DNS process is necessarily performed in an internet service.
In addition, a conventional mobile terminal has a configuration using a DNS directly inputted by a user. Accordingly, there is a problem in that an internet service is delayed according to a distance between a mobile terminal requesting the internet service and the DNS since the mobile terminal is also required to receive the IP address by accessing the DNS determined by the user when the mobile terminal using the mobile IP guaranteeing mobility moves around various networks.
While receiving an IP address, a gateway, and a router address from a mobile agent when the mobile terminal performs a mobile IP registration by using a mobile IPv4 message, the mobile terminal may not update the DNS address since it does not include an index for requesting the DNS address in a standard message format.
PCT Publication No. WO 02/082207 entitled “Discovering an address of a name server” discloses a method for providing a mobile terminal with DNS address information, in which the IP address of the DNS is received by changing contents of a standard registration reply message of the mobile IP or by using an internet protocol control protocol (IPCP) message in the mobile communication network having a packet service node for establishing a session with the mobile terminal. However, in this patent, an additional message for providing the DNS information is problematically required to be defined since the DNS EP address is received by defining a predetermined authentication server and a message.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.